66841021 has 6 divisors (see below), whose sum is σ = 72378330. Its totient is φ = 61699248.

The previous prime is 66841007. The next prime is 66841037. The reversal of 66841021 is 12014866.

It can be written as a sum of positive squares in 3 ways, for example, as 1473796 + 65367225 = 1214^2 + 8085^2 .

It is not a de Polignac number, because 66841021 - 2⁹ = 66840509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66841001) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 197586 + ... + 197923.

It is an arithmetic number, because the mean of its divisors is an integer number (12063055).

Almost surely, 2^66841021 is an apocalyptic number.

It is an amenable number.

66841021 is a deficient number, since it is larger than the sum of its proper divisors (5537309).

66841021 is a wasteful number, since it uses less digits than its factorization.

66841021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395535 (or 395522 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 66841021 is about 8175.6358162531. The cubic root of 66841021 is about 405.8333114174.

Adding to 66841021 its reverse (12014866), we get a palindrome (78855887).

The spelling of 66841021 in words is "sixty-six million, eight hundred forty-one thousand, twenty-one".